2025 IGCSE 0580 May/June P41 Q20

The diagram shows a pyramid \(OABCD\).

The pyramid has a square base, \(ABCD\), with sides \(10.5\text{ cm}\).

The vertex \(O\) is vertically above the centre of the base, \(M\).

The height of the pyramid is \(24\text{ cm}\).

1. Calculate the angle that \(OA\) makes with the base.[4]
2. The diagram shows a frustum of the pyramid \(OABCD\).
   The height of the frustum is \(16\text{ cm}\).
   Calculate the volume of the frustum.[5]